May I apply the term "lean" if I adapt lean startup concepts & apply them outside entrepreneurship w/o infringing on any legal protections of "lean"?

This is a tricky question as you are entering a gray area if you are using material from Book Z to inspire your own book. Derivatives works are highly litigated and there is case law that you could turn to to help you make this decision but based on your example its going to be a fine line. You would have to be able to distinguish the products as two very separate works. Since the original book Z is inspiring your new book this may be hard to do. It might actually be easier to talk with the original author about your future plans and develop an agreement between the two of you where he waives any claims he might have here in exchange for recognition in your book. Just an idea--FYI- this is NOT LEGAL ADVICE. You should consult with an attorney in more detail here.

Mobile app that has launched: You need ALL of the following: 1) Trending towards or at 100000 installs within first 90 days of launch; 2) Day 30 retention rate of at least 20% 3) Core "MTM" (metric that matters) healthy (dependent on business model, usage model etc) 4) Evidence that growth is just "getting started" with plenty of upside left. Happy to talk more in a call.

Wow, lots of questions here. Let me try to hit them in order: "Should I get a job or find investors?" IF you have access to enough investor capital (not debt and not your savings) and you can get to MVP and still maintain ownership of a sizable majority of the business then do it. IF that means debt financing then only use the debt lines the cost of which can be carried by returns generated by the use of funds. I would prefer to offer a convertible note to prospective investors that can be easily extended throughout both friends and family and seed rounds (up to $2M to $3M) to get to proof in the market. If you can get to revenue and earnings fast enough then you can avoid equity dilution all together. IF you cannot secure that find of funding AND you cannot produce enough revenue from your business to deliver sufficient earnings for you to live on, then by all means, you should find a way to make the money you need and not burn all your savings or mortgage your home If that means short term contract work that's great. Particularly if you can find log term work that is relevant to the business you're building. If that means taking a job then do that. IF you do that, then yes, be transparent with your employer and let them know you're working on your own business also. Hope this helps....

Disclaimer: I'm not an intellectual property attorney - and I am not attempting to, nor qualified to give legal advice. That said - here is what I know on the subject. Copyright was once explained to me as a bundle of sticks, where each stick was a different right. Two sticks that might be important in this situation would be: 1. Distribution Rights: Creating the sheet music in itself may be harmless, but copyright does cover right to distribute - and so your idea to distribute for profit may infringe upon this right. 2. Derivative Works: Copyright also gives the owner the right to create derivative works based on the original - so even if your version is different - it becomes an issue of "how different" - so you may also be infringing on this right. One path forward is to determine who owns these rights (the original artists or label often sell the rights) and license the right to produce and sell the sheet music. My guess is this could be cost and time prohibitive. Another would be to see who is already selling sheet music for these songs - and simply act as an affiliate, taking a portion of the revenues per sale. Consider trying the affiliate route first, to determine how many of these sales you generate from your audience, before going to the trouble of licensing the content etc. I'd be happy to discuss ways that you can validate demand within your population before you do either, and recommend doing so with or without my input. Cheers, Ryan

My answer will be short: Definitely an app. I'll be more than happy to discuss details further.